W ith most of the winter snow falling last October, plants bursting into bloom in February, and more May showers than April ones, the weather report has become our least reliable signal of changing seasons.

What’s the surefire method, then, for gauging that we’ve entered a new phase of the year? Not our pets shedding their winter coats but rather our colleges and universities shedding their students.

Yale University’s 311th commencement unfolds over the next three days, May 19-21. Sunday’s Class Day speech by newswoman Barbara Walters and Monday’s commencement exercises will both be streamed live.

Yale students may be the ones you’re most likely to notice downtown, but Yale is hardly the only college or university holding a commencement this week. Southern Connecticut State University’s graduate school ceremonies were last evening, followed by the undergraduates getting their diplomas at 10:15 a.m. this morning. Quinnipiac University’s undergraduate commencement ceremonies are Sunday at 10 a.m. and 3 p.m., while Albertus Magnus College’s take place the same day at 2 p.m.

May is a time of springy wonderment in college towns. It’s when the sight of a young person carrying a chair, or a tall lamp, for several blocks on a main downtown street, is as natural as seeing a robin sing outside your window. It’s when entire libraries of discarded textbooks appear on lawns like new-grown grass. It’s when “For Rent” signs appear on the residential streets closest to campus as if they were sunflowers punctuating spring gardens. It’s when trashcans and dumpsters explode like geysers in national parks, expelling the most extraordinary items, from half a desk (where’s the other half?) to human-sized stuffed animals to chemical beakers and purloined dining-hall dishware. Taboo dorm accessories such as halogen lamps or toaster ovens are often mutilated before being discarded, in a vain attempt to hide the evidence.

Once the ephemeral possessions have hit the streets, so have their owners, angling for U-Haul trucks and packing cases. The lines at the Yale post office are a museum of oddly shaped, oddly taped boxes, envelopes and tubes. Thus begins the moving-out process, the shifting tide which turns the sidewalks of spring into the sort of exodus we associate with other species such as lemmings or salmon or the swallows of Capistrano.

But the jettisoning of stuff is not a bleak sudden sharp expulsion. It’s simultaneous with a burst of vital energy on the streets.

For a few weeks between reading period and graduation ceremonies, there’s an unmissable excess of collegiate hustle-bustle downtown: tuxedo-clad musicians lugging upright basses or kettle drums across Elm Street for classical recitals or musical theater events. The Spring Fling concerts and similar year-end celebrations, where dance music infects the air throughout downtown. Casual Frisbee games denote some of the final carefree moments these students may share with their classmates.

A whole lot of catching up and winding down.

Then… a whole lot less. Hordes of students march en masse across New Haven Green on the traditional winding route to the graduation ceremonies on Old Campus. Hours later, they just vanish. Some jump into their parents’ cars, diplomas in hand. Some head off solo into the unknown. Even faculty members skedaddle, off on vacation, or to summer teaching gigs in other climes.

Sure, there are a couple of weekends of alumni reunions in late May and early June, but that’s a whole different vibe. The lightpoles of Broadway are strung with white and blue ribbons, the iron gates of the colleges are flung open. The effect is more like a mirage than a reality, a spectre of the present-day, in-the-moment vitality of just a few weeks earlier.

It’s commencement day when the season truly changes, when the winds start blowing from other directions, when once-populous areas grow suddenly quiet and events like the International Festival of Arts & Ideas, Ideat Village and the Concerts on the Green and others take over.

Not a loss, not a snub, not a banishment. A change. The most reliable change in consciousness our city knows.

About Christopher Arnott

Christopher Arnott has written about arts and culture in Connecticut for over 25 years. His journalism has won local, regional and national awards, and he has been honored with an Arts Award from the Arts Council of Greater New Haven. He posts daily at his own sites www.scribblers.us and New Haven Theater Jerk (www.scribblers.us/nhtj).